Indoor unit for air-conditioning apparatus and air-conditioning apparatus including the indoor unit

ABSTRACT

An indoor unit for air-conditioning that may suppress the discharge of dewdrops into a conditioned space. An indoor unit including a casing having an air inlet in an upper portion thereof and an air outlet in a lower portion of a front face thereof, a fan, a heat exchange, and a louver configured to redirect air blown out of the air outlet in a vertical direction. The louver includes a main louver and a sub-louver. In a state where the main louver is level, the sub-louver is provided below the main louver. A leeward end of the sub-louver is positioned forward by a first predetermined distance with respect to a virtual perpendicular line passing through a windward end of the main louver. A windward end of the sub-louver is positioned rearward by a second predetermined distance with respect to the virtual perpendicular line.

TECHNICAL FIELD

The present invention relates to an indoor unit intended for anair-conditioning apparatus and to an air-conditioning apparatusincluding the indoor unit.

Background Art

Known indoor units for air-conditioning apparatuses include axial-flowor mixed-flow fans functioning as air-sending devices that allow air inconditioned spaces to flow through the indoor units. An example of suchan indoor unit for an air-conditioning apparatus is as follows. “Anindoor unit 40 includes a casing 1 having an air inlet 2 in an upperportion thereof and an air outlet 3 in a lower portion of a front facethereof, an axial-flow or mixed-flow fan 4 provided in the casing 1 at aposition on the downstream side of the air inlet 2, and a heat exchanger5 provided in the casing 1 at a position on the downstream side of thefan 4 and on the upstream side of the air outlet 3 and configured toexchange heat between air blown by the fan 4 and a refrigerant” (seePatent Literature 1). Such a known indoor unit for an air-conditioningapparatus also includes a louver (also referred to as vane in PatentLiterature 1) provided at the air outlet. The louver redirects the airblown out of the air outlet in the vertical direction.

CITATION LIST Patent Literature

[Patent Literature 1] WO2010/089920 (Abstract, Paragraph [0012], andFIG. 1)

SUMMARY OF INVENTION Technical Problem

As disclosed by Patent Literature 1, the axial-flow or mixed-flow fan isprovided at a position on the downstream side of the air inlet and onthe upstream side of the heat exchanger. Furthermore, the axial-flow ormixed-flow fan is oriented such that the air-sending direction thereof(for example, the direction of the rotational axis of the fan if the fanis an axial-flow fan) is orthogonal to the air inlet provided in theupper portion of the casing. That is, in the known indoor unit includingan axial-flow or mixed-flow fan, the air having flowed through the heatexchanger, that is, the air flowing toward the air outlet, tends to flowin the vertical direction of the casing. Therefore, the known indoorunit including an axial-flow or mixed-flow fan has the following problemthat may occur in a case where the air blown out of the air outlet isredirected in the vertical direction by a louver.

Some of the air having flowed into the air outlet hits the upper surfaceof the louver and is redirected in such a manner as to be blown out ofthe air outlet. The rest of the air having flowed into the air outletbut not having hit the upper surface of the louver is attracted towardthe lower surface of the louver by the flow of the air that has hit theupper surface of the louver and by a flow of the air produced along alower member defining the air outlet. Therefore, in the known indoorunit including an axial-flow or mixed-flow fan, the air flowing into theair outlet and the air flowing out of the air outlet tend to be angledwith respect to each other because the flow of the air into the airoutlet tends to be produced in the vertical direction of the casing.Consequently, the air flowing below the louver tends to be separatedfrom the lower surface of the louver. Hence, when the indoor unit is incooling operation, the louver is cooled by cool air (the air cooled bythe heat exchanger) that has hit the upper surface of the louver,whereby warm air from the conditioned space gathering in an area belowthe louver where flow separation may occur is cooled through the louver.This increases the probability that dew condensation may occur on thelower surface of the louver (in particular, a portion of the lowersurface of the louver that faces the flow-separation area). Thus, theknown indoor unit including an axial-flow or mixed-flow fan has aproblem in that dewdrops produced on the lower surface of the louver maygather and form larger dewdrops, and such dewdrops may be dischargedinto the conditioned space.

The present invention is to solve the above problem and to provide anindoor unit for an air-conditioning apparatus in which the discharge ofdewdrops into a conditioned space that may occur in a cooling operationis suppressed, and an air-conditioning apparatus including the indoorunit.

Solution to Problem

An indoor unit for an air-conditioning apparatus according to thepresent invention includes a casing having an air inlet in an upperportion thereof and an air outlet in a lower portion of a front facethereof, an air-sending device provided in the casing and configured tosuction air into the casing via the air inlet and to blow the air out ofthe casing via the air outlet, a heat exchanger provided in the casingand configured to exchange heat between the air suctioned into thecasing and a refrigerant, and a louver provided at the air outlet andconfigured to redirect the air blown out of the air outlet in a verticaldirection. The louver includes a main louver and a sub-louver that eachhave a plate shape and are each configured to rotate around a rotationalaxis extending in a lateral direction of the casing. In a state where avirtual line connecting a leeward end and a windward end of the mainlouver is level, the sub-louver is provided below the main louver; aleeward end of the sub-louver is positioned forward by a firstpredetermined distance with respect to a virtual perpendicular linepassing through the windward end of the main louver; and a windward endof the sub-louver is positioned rearward by a second predetermineddistance with respect to the virtual perpendicular line passing.

An air-conditioning apparatus according to the present inventionincludes the above indoor unit for an air-conditioning apparatus.

Advantageous Effects of Invention

According to the present invention, the louver includes the main louverand the sub-louver that each have a plate shape and are each configuredto rotate around the rotational axis extending in the lateral directionof the casing. In the state where the virtual line connecting theleeward end and the windward end of the main louver is level, thesub-louver is provided below the main louver; the leeward end of thesub-louver is positioned forward by the first predetermined distancewith respect to the virtual perpendicular line passing through thewindward end of the main louver; and the windward end of the sub-louveris positioned rearward by the second predetermined distance with respectto the virtual perpendicular line. Therefore, some of the air that hasflowed into the air outlet and has not hit the upper surface of the mainlouver hits the upper surface of the sub-louver and flows along theupper surface of the sub-louver. That is, the air that has hit the uppersurface of the sub-louver is attracted toward the lower surface of themain louver and flows along the lower surface of the main louver. Hence,the air flowing below the main louver does not tend to be separated fromthe lower surface of the main louver. Thus, in the cooling operation,the occurrence of dew condensation on the lower surface of the mainlouver is suppressed, and the discharge of dewdrops into a conditionedspace is hence suppressed.

The application of the present invention is not limited to indoor unitsincluding axial-flow or mixed-flow fans. The type of the air-sendingdevice according to the present invention is not limited, and thepresent invention is applicable to indoor units including various typesof air-sending devices.

For example, in an indoor unit including a cross-flow fan functioning asan air-sending device, the cross-flow fan is provided on the downstreamside of the heat exchanger (i.e., between the heat exchanger and the airoutlet). Therefore, in the indoor unit including a cross-flow fan, theair flowing into the air outlet can be more easily redirected in such amanner as to be blown out of the air outlet, compared with an indoorunit including an axial-flow or mixed-flow fan, by tilting the directionin which the cross-flow fan blows air. However, since the direction ofthe air blown out of the air outlet changes, the direction in which thecross-flow fan blows air and the direction in which the air is blown outof the air outlet into the conditioned space cannot be made the sameconstantly. That is, a louver is also necessary in the indoor unitincluding a cross-flow fan so as to redirect the air flowing into theair outlet. Therefore, in the indoor unit including a cross-flow fanalso, if the angle at which the airflow is redirected by the louverbecomes large, the airflow may be separated from the lower surface ofthe louver and dew condensation may occur on the lower surface of thelouver in the cooling operation. Moreover, dewdrops on the lower surfaceof the louver may gather and form larger dewdrops, and such dewdrops maybe discharged into the conditioned space. Considering suchcircumstances, the present invention is also very effective for theindoor unit including a cross-flow fan.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a vertical sectional view of an indoor unit for anair-conditioning apparatus according to Embodiment 1 of the presentinvention.

FIG. 2 is a perspective appearance view of the indoor unit for anair-conditioning apparatus according to Embodiment 1 of the presentinvention.

FIG. 3 includes diagrams illustrating a louver included in the indoorunit for an air-conditioning apparatus according to Embodiment 1 of thepresent invention.

FIG. 4 illustrates airflows produced near an air outlet of the indoorunit for an air-conditioning apparatus according to Embodiment 1 of thepresent invention.

FIG. 5 illustrates how a predetermined distance L4 is set for the louverincluded in the indoor unit for an air-conditioning apparatus accordingto Embodiment 1 of the present invention.

FIG. 6 is a vertical sectional view of an indoor unit for anair-conditioning apparatus according to Embodiment 2 of the presentinvention.

FIG. 7 is a vertical sectional view illustrating a modification of theindoor unit for an air-conditioning apparatus according to Embodiment 2of the present invention.

DESCRIPTION OF EMBODIMENTS Embodiment 1

An air-conditioning apparatus (more specifically, an indoor unit for anair-conditioning apparatus) according to Embodiment 1 of the presentinvention will now be described. Embodiment 1 of the present inventionconcerns an exemplary case of a wall-mounted indoor unit that includesan axial-flow or mixed-flow fan functioning as an air-sending device.The shapes, sizes, and so forth of units (or elements included in theunits) illustrated in the drawings may vary depending on circumstances.

FIG. 1 is a vertical sectional view of an indoor unit 100 for anair-conditioning apparatus according to Embodiment 1 of the presentinvention. FIG. 2 is a perspective appearance view of the indoor unit100. FIG. 3 includes diagrams illustrating a louver 10 included in theindoor unit 100. FIG. 3( a) is an enlarged view of the louver 10illustrated in FIG. 1. FIG. 3( b) is an upper perspective view of thelouver 10 illustrated in FIG. 3( a). FIG. 3( c) is a lower perspectiveview of the louver 10 illustrated in FIG. 3( a).

A configuration of the indoor unit 100 will be described with referenceto FIGS. 1 to 3. In Embodiment 1, the left side in FIG. 1 is defined asthe front side of the indoor unit 100.

The indoor unit 100 supplies conditioned air into a conditioned space,such as a room, by utilizing a refrigeration cycle through which arefrigerant circulates. The indoor unit 100 basically includes thefollowing: a casing 1 having an air inlet 2 via which room air issuctioned into the casing 1 and an air outlet 3 via which theconditioned air is supplied into the conditioned space, a fan 4 providedin the casing 1 and configured to suction the room air via the air inlet2 and to cause the conditioned air to be blown out of the air outlet 3,a heat exchanger 5 provided in a flow path extending from the fan 4 tothe air outlet 3 and configured to produce the conditioned air byexchanging heat between the refrigerant and the room air, and the louver10 configured to redirect the flow of the conditioned air in thevertical direction such that the conditioned air is blown out of the airoutlet 3. The air inlet 2 is provided in an upper portion of the casing1. The air outlet 3 is provided in a lower portion of the casing 1 (morespecifically, in a lower portion of the front face of the casing 1).

The fan 4, which is, for example, an axial-flow or mixed-flow fan, isprovided at a position on the downstream side of the air inlet 2 and onthe upstream side of the heat exchanger 5. In general, many indoor unitsfor air-conditioning apparatuses do not have large fans because thespaces in which the indoor units can be installed are limited.Therefore, in Embodiment 1, a plurality of fans 4 having moderate sizesare provided in parallel so that a desired volume of airflow can beproduced. More specifically, as illustrated in FIG. 2, the indoor unit100 according to Embodiment 1 includes three fans 4 arranged in parallelin the lateral direction of the casing 1.

The heat exchanger 5 is provided on the leeward side of the fans 4. Theheat exchanger 5 provided in the casing 1 has a substantially A shape insectional view. Such a sectional shape of the heat exchanger 5 is onlyexemplary and may alternatively be a substantially M or N shape, forexample.

The louver 10 is provided at the air outlet 3 and includes a main louver11 and a sub-louver 12. The main louver 11 has a substantially flatplate shape whose longitudinal direction corresponds to the lateraldirection of the casing 1. The sub-louver 12 also has a substantiallyflat plate shape whose longitudinal direction corresponds to the lateraldirection of the casing 1, as with the main louver 11. The main louver11 and the sub-louver 12 are connected to each other at the lateral endsthereof with ribs 14. In other words, the main louver 11 and thesub-louver 12 according to Embodiment 1 are provided as an integralbody. Furthermore, in Embodiment 1, the sub-louver 12 has a width L2smaller than a width L1 of the main louver 11.

The main louver 11 and the sub-louver 12 may each have a slightly curvedshape in side sectional view.

The main louver 11 and the sub-louver 12 configured as above arearranged as illustrated in FIG. 3. Specifically, the main louver 11 andthe sub-louver 12 extend substantially parallel to each other. Forexample, in the case where the main louver 11 and the sub-louver 12 eachhave a slightly curved shape in side sectional view, a virtual lineconnecting a windward end 11 a and a leeward end 11 b of the main louver11 and a virtual line connecting a windward end 12 a and a leeward end12 b of the sub-louver 12 extend substantially parallel to each other.Furthermore, in Embodiment 1, the main louver 11 and the sub-louver 12are at a predetermined distance L3 of 5 mm to 10 mm from each other.

In a case where the virtual line connecting the windward end 11 a andthe leeward end 11 b of the main louver 11 is level, the leeward end 12b of the sub-louver 12 is positioned forward by a predetermined distanceL4 with respect to a virtual perpendicular line 11 c passing through thewindward end 11 a of the main louver 11. Furthermore, in the case wherethe virtual line connecting the windward end 11 a and the leeward end 11b of the main louver 11 is level, the windward end 12 a of thesub-louver 12 is positioned rearward by a predetermined distance L5 withrespect to the virtual perpendicular line 11 c passing through thewindward end 11 a of the main louver 11.

Furthermore, according to Embodiment 1, in the case where the virtualline connecting the windward end 11 a and the leeward end 11 b of themain louver 11 is level as illustrated in FIG. 1, that is, in a casewhere the virtual line connecting the windward end 12 a and the leewardend 12 b of the sub-louver 12 is level, an edge (lower edge) of a lowermember 3 b defining the air outlet 3 is positioned forward by apredetermined distance L6 with respect to a virtual perpendicular line12 c passing through the windward end 12 a of the sub-louver 12 (seeFIG. 1).

The predetermined distance L4 corresponds to the first predetermineddistance according to the present invention. The predetermined distanceL5 corresponds to the second predetermined distance according to thepresent invention. The predetermined distance L6 corresponds to thethird predetermined distance according to the present invention. Aspecific method of setting the predetermined distances L4, L5, and L6will be described separately below in conjunction with description ofoperations.

The ribs 14 included in the louver 10 have pins 13, respectively,projecting from the outer sides thereof. The pins 13, that isprojections, are rotatably supported by, for example, sidewalls of thecasing 1. That is, the main louver 11 and the sub-louver 12 areconfigured to rotate around the pins 13 provided on a virtual lineextending in the lateral direction of the casing 1. The main louver 11and the sub-louver 12 are driven by a motor or the like (notillustrated).

The indoor unit 100 according to Embodiment 1 also includes astraightening vane 6 provided on an upper member 3 a defining the airoutlet 3. The straightening vane 6 guides the air having flowed into theair outlet 3 toward the exit of the air outlet 3.

(Description of Operations)

Operations performed by the indoor unit 100 configured as above will nowbe described.

When the fans 4 are driven to rotate, the room air is suctioned into thecasing 1 via the air inlet 2. The room air is blown by the fans 4 andflows into the heat exchanger 5 provided on the downstream side. Theroom air having flowed into the heat exchanger 5 is cooled in a coolingoperation or is heated in a heating operation by the refrigerant flowingthrough the heat exchanger 5. The air thus conditioned flows into theair outlet 3. The conditioned air having flowed into the air outlet 3 isredirected in the vertical direction by the louver 10 (i.e., by the mainlouver 11 and the sub-louver 12) and is blown out of the air outlet 3into the conditioned space (i.e., to the outside of the casing 1).Airflows produced near the air outlet 3 in this process are illustratedin FIG. 4.

FIG. 4 illustrates the airflows produced near the air outlet 3 of theindoor unit 100 for an air-conditioning apparatus according toEmbodiment 1 of the present invention. FIG. 4 is a sectional viewcorresponding to FIG. 1.

Each fan 4, which is an axial-flow or mixed-flow fan, is oriented suchthat the air-sending direction thereof (for example, the direction ofthe rotational axis of the fan 4 if the fan 4 is an axial-flow fan) isorthogonal to the air inlet 2 provided in the upper portion of thecasing 1. Therefore, the conditioned air having flowed through the heatexchanger 5 generally tends to flow in a vertical direction of thecasing 1, although the direction of the flow slightly changes whenpassing through the heat exchanger 5. Hence, the direction in which theconditioned air flows into the air outlet 3 is close to the verticaldirection of the casing 1 on the upstream side of the louver 10,although the flow is redirected toward the exit of the air outlet 3 bythe straightening vane 6. That is, the conditioned air having flowedinto the air outlet 3 flows as follows.

Some of the conditioned air having flowed into an area near the uppermember 3 a defining the air outlet 3 is redirected toward the exit ofthe air outlet 3 by the straightening vane 6 while being pushed upwardby airflow 9B, to be described below, thereby flowing along the uppermember 3 a defining the air outlet 3 (see airflow 9A illustrated in FIG.4). Some of the conditioned air having flowed into the air outlet 3 onthe rear side with respect to the airflow 9A hits the upper surface ofthe main louver 11 and flows along the upper surface of the main louver11 (see the airflow 9B illustrated in FIG. 4). Some of the conditionedair having flowed into the air outlet 3 on the rear side with respect tothe airflow 9B flows without hitting the upper surface of the mainlouver 11.

The air flowing on the rear side with respect to the airflow 9B tends toflow along the lower surface of the main louver 11. If the direction ofsuch airflow is angled with respect to the direction in which the mainlouver 11 extends (i.e., the direction in which the conditioned air isblown out of the air outlet 3), the airflow may be separated from thelower surface of the main louver 11. Therefore, when the indoor unit 100is in cooling operation, the main louver 11 is cooled by the cool airthat hits the upper surface of the main louver 11, whereby warm room airgathering in an area below the main louver 11 where flow separation mayoccur is cooled through the main louver 11. This increases theprobability that dew condensation may occur on the lower surface of themain louver 11 (in particular, a portion of the lower surface of themain louver 11 that faces the flow-separation area). If dewdropsproduced on the lower surface of the main louver 11 gather and formlarger dewdrops, such dewdrops may be discharged into the room.

In Embodiment 1, however, since the sub-louver 12 is provided, some ofthe conditioned air that has not hit the upper surface of the mainlouver 11 hits the upper surface of the sub-louver 12 and flows alongthe upper surface of the sub-louver 12 (see airflow 9C illustrated inFIG. 4). That is, the conditioned air having hit the upper surface ofthe sub-louver 12 flows between the main louver 11 and the sub-louver 12while being attracted toward and flows along the lower surface of themain louver 11. Therefore, the conditioned air flowing along the lowersurface of the main louver 11 does not tend to be separated from thelower surface of the main louver 11. Thus, in the cooling operation, theoccurrence of dew condensation on the lower surface of the main louver11 is suppressed, and the discharge of dewdrops into the room is hencesuppressed. Since the predetermined distance L3 between the main louver11 and the sub-louver 12 is set to 5 mm to 10 mm, flow separation doesnot tend to occur between the main louver 11 and the sub-louver 12.Consequently, the pressure loss in the conditioned air flowing betweenthe main louver 11 and the sub-louver 12 is reduced. That is, theresistance in the flow path for the airflow 9C defined between the mainlouver 11 and the sub-louver 12 is reduced.

In Embodiment 1, some of the conditioned air that has not hit the uppersurface of the sub-louver 12 hits the lower member 3 b defining the airoutlet 3 and flows along the lower member 3 b defining the air outlet 3(see airflow 9D illustrated in FIG. 4). That is, the conditioned airhaving hit the lower member 3 b defining the air outlet 3 is attractedtoward the lower surface of the sub-louver 12 and flows along the lowersurface of the sub-louver 12. Therefore, the conditioned air flowingbelow the sub-louver 12 does not tend to be separated from the lowersurface of the sub-louver 12. Thus, in the cooling operation, theoccurrence of dew condensation on the lower surface of the sub-louver 12is also suppressed, and the discharge of dewdrops into the room isfurther suppressed.

Referring to FIG. 5, as an angle α of the louver 10 (i.e., the mainlouver 11 and the sub-louver 12) with respect to the level becomescloser to perpendicular, the predetermined distance L4 becomes smaller.As the angle α of the louver 10 further becomes further close toperpendicular, the predetermined distance L4 becomes less than zero;that is, the windward end 11 a of the main louver 11 and the leeward end12 b of the sub-louver 12 become not overlapping each other in thevertical direction in side view. Meanwhile, as the angle α of the louver10 (i.e., the main louver 11 and the sub-louver 12) becomes closer toperpendicular, the difference between the angle of the conditioned airflowing into the air outlet 3 and the angle of the conditioned airflowing out of the air outlet 3 becomes smaller. Therefore, flowseparation does not tend to occur below the main louver 11. Hence, inEmbodiment 1, the predetermined distance L4 is set so as to become zeroor larger when the angle of the conditioned air flowing into the airoutlet 3 (for example, the angle of the rotational axis of the fan 4 ifthe fan 4 is an axial-flow fan) and the angle of the main louver 11become respective values that allow dewdrops to be discharged into theroom because of the effect produced in the flow-separation area belowthe main louver 11. Similarly, in Embodiment 1, the predetermineddistance L6 is set so as to become zero or larger when the angle of theconditioned air flowing into the air outlet 3 (for example, the angle ofthe rotational axis of the fan 4 if the fan 4 is an axial-flow fan) andthe angle of the sub-louver 12 become respective values that allowdewdrops to be discharged into the room because of the effect producedin the flow-separation area below the sub-louver 12. Furthermore, thepredetermined distance L5 is set on the basis of the predetermineddistance L4 and the width L2 of the sub-louver 12. In addition, the mainlouver 11 and the sub-louver 12 according to Embodiment 1 are arrangedsuch that the predetermined distance L4 becomes zero when the angle α ofthe main louver 11 with respect to the level (see FIG. 5) is 55 degrees.In other words, supposing that the angle of the conditioned air flowinginto the air outlet 3 is perpendicular, the main louver 11 and thesub-louver 12 are arranged such that the predetermined distance L4becomes zero when the angle formed between the virtual perpendicularline 11 c and the main louver 11 becomes 35 degrees. Similarly, thesub-louver 12 and the edge of the lower member 3 b defining the airoutlet 3 are arranged such that the predetermined distance L6 becomeszero when the angle of the sub-louver 12 with respect to the levelbecomes 55 degrees. In other words, supposing that the angle of theconditioned air flowing into the air outlet 3 is perpendicular, thesub-louver 12 and the edge of the lower member 3 b defining the airoutlet 3 are arranged such that the predetermined distance L6 becomeszero when the angle formed between the virtual perpendicular line 12 cand the sub-louver 12 becomes 35 degrees.

In the indoor unit 100 according to Embodiment 1, the louver 10 includesthe main louver 11 and the sub-louver 12. Furthermore, in the case wherethe virtual line connecting the windward end 11 a and the leeward end 11b of the main louver 11 is level, the leeward end 12 b of the sub-louver12 is positioned forward by the predetermined distance L4 with respectto the virtual perpendicular line 11 c passing through the windward end11 a of the main louver 11. Therefore, in the cooling operation, theoccurrence of dew condensation on the lower surface of the main louver11 is suppressed, and the discharge of dewdrops into the room is hencesuppressed.

Furthermore, the width L2 of the sub-louver 12 is smaller than the widthL1 of the main louver 11. Therefore, even if dew condensation occurs onthe lower surface of the sub-louver 12, dewdrops produced on the lowersurface of the sub-louver 12 do not tend to form larger dewdrops. Hence,the discharge of dewdrops into the room is further suppressed.

Furthermore, in the case where the virtual line connecting the windwardend 12 a and the leeward end 12 b of the sub-louver 12 is level, theedge (lower edge) of the lower member 3 b defining the air outlet 3 ispositioned forward by the predetermined distance L6 with respect to thevirtual perpendicular line 12 c passing through the windward end 12 a ofthe sub-louver 12. Therefore, in the cooling operation, the occurrenceof dew condensation on the lower surface of the sub-louver 12 is alsosuppressed, and the discharge of dewdrops into the room is furthersuppressed.

Furthermore, since the straightening vane 6 is provided on the uppermember 3 a defining the air outlet 3, the conditioned air having flowedinto the air outlet 3 is redirected toward the exit of the air outlet 3by the straightening vane 6. This reduces the difference between theangle of the conditioned air flowing into the air outlet 3 and the angleof the conditioned air flowing out of the air outlet 3. Therefore, inthe cooling operation, the occurrence of dew condensation on the lowersurfaces of the main louver 11 and the sub-louver 12 is furthersuppressed, and the discharge of dewdrops into the room is furthersuppressed.

While the main louver 11 and the sub-louver 12 according to Embodiment 1share the common pins 13 that together define one rotational axis, themain louver 11 and the sub-louver 12 may alternatively have respectiverotational axes. That is, even if the main louver 11 and the sub-louver12 have respective rotational axes, the effects described in Embodiment1 are produced, as long as the main louver 11 and the sub-louver 12 arearranged as described above.

While Embodiment 1 of the present invention concerns a case where theindoor unit 100 includes the fans 4 that are axial-flow or mixed-flowfans, it is obvious that the present invention can be embodiedregardless of the type of the fans included in the indoor unit. In anindoor unit including a louver, the flow of air is redirected in such amanner as to be blown out of the air outlet, regardless of the type offans. Therefore, if the angle at which the airflow is redirected by thelouver is large, the airflow produced below the louver may be separatedfrom the lower surface of the louver. This may lead to dew condensationon the lower surface of the louver in the cooling operation. Dewdropsproduced on the lower surface of the louver may gather and form largerdewdrops. Such dewdrops may be discharged into the conditioned space.Considering such circumstances, the present invention is effective insuppressing the discharge of dewdrops into the room in all types ofindoor units including louvers.

Embodiment 2

In terms of design improvement, air outlets of some known indoor unitsare closed by louvers when the indoor units are not in operation. Theair outlet 3 of the indoor unit 100 including the main louver 11 and thesub-louver 12 may be closed as described below. In Embodiment 2,elements that are the same as those according to Embodiment 1 are notspecifically described, and like functions and elements are denoted bylike reference numerals and characters. The term “close” used inEmbodiment 2 implies that the inside of the indoor unit 100 is concealedby the louver 10 and does not imply that the air outlet 3 of the indoorunit 100 is completely closed by the louver 10.

In the indoor unit 100 according to Embodiment 1, the air outlet 3 is tobe closed by the louver 10 by rotating the louver 10. In such a case,the louver 10 may be rotated in such a direction that the windward endof the louver 10 moves toward the lower member 3 b defining the airoutlet 3 (hereinafter, referring to FIG. 1, this direction of rotationis referred to as clockwise direction). Alternatively, the louver 10 maybe rotated in such a direction that the windward end of the louver 10moves toward the upper member 3 a defining the air outlet 3(hereinafter, referring to FIG. 1, this direction of rotation isreferred to as counterclockwise direction).

In the case where the louver 10 is rotated in the clockwise direction,since the indoor unit 100 is configured such that the edge of the lowermember 3 b defining the air outlet 3 projects forward so that theoccurrence of dew condensation on the sub-louver 12 is suppressed, thesub-louver 12 and the lower member 3 b defining the air outlet 3 mayinterfere with each other, preventing the louver 10 from covering theair outlet 3.

In contrast, in the case where the louver 10 is rotated in thecounterclockwise direction so as to cover the air outlet 3, the windwardend 11 a of the main louver 11 may need to reach a position that isforward with respect to the edge of the upper member 3 a defining theair outlet 3 so that the inside of the casing 1 is concealed when seenfrom below the main louver 11. In such a case, the windward end 11 a ofthe main louver 11 first passes below the edge of the upper member 3 adefining the air outlet 3 and then reaches the position that is forwardof the edge of the upper member 3 a defining the air outlet 3.Therefore, consideration needs to be given for preventing theinterference between the windward end 11 a of the main louver 11 and theupper member 3 a defining the air outlet 3. Consequently, a large gapmay need to be provided between the windward end 11 a of the main louver11 and the edge of the upper member 3 a defining the air outlet 3. Insuch a case, the inside of the casing 1 is exposed through the gap,deteriorating the design.

Hence, in Embodiment 2, the air outlet 3 is covered by the louver 10 asdescribed below, and the design is thus improved.

FIG. 6 is a vertical sectional view of an indoor unit 100 for anair-conditioning apparatus according to Embodiment 2 of the presentinvention.

As illustrated in FIG. 6, the indoor unit 100 according to Embodiment 2is configured as follows. The louver 10 is configured to rotate in thecounterclockwise direction in such a manner as to cover the air outlet3. Furthermore, in a state where the windward end 11 a of the mainlouver 11 faces the edge of the upper member 3 a defining the air outlet3, a gap is produced between the windward end 11 a of the main louver 11and the upper member 3 a defining the air outlet 3 for the prevention ofinterference therebetween. Furthermore, the main louver 11 and thesub-louver 12 are configured to rotate around the common pins 13.Therefore, when the louver 10 is rotated in the counterclockwisedirection, the windward end 12 a of the sub-louver 12 rotates about thepins 13 and on the outer side with respect to the windward end 11 a ofthe main louver 11, and comes into contact with the upper member 3 adefining the air outlet 3. Accordingly, the gap between the windward end11 a of the main louver 11 and the edge of the upper member 3 a definingthe air outlet 3 is covered by the sub-louver 12. Thus, when the indoorunit 100 is not in operation, the air outlet 3 is covered by the louver10, providing the beauty of appearance. Hence, the indoor unit 100according to Embodiment 2 has improved design in the state where theindoor unit 100 is not in operation.

In FIG. 6, the louver 10 is stopped by directly bringing the windwardend 12 a of the sub-louver 12 into contact with the upper member 3 adefining the air outlet 3. Alternatively, referring to FIG. 7, thelouver 10 may be stopped by bringing the windward end 12 a of thesub-louver 12 into contact with a stopper 7 projecting from the uppermember 3 a defining the air outlet 3. In the case where the louver 10 isstopped by directly bringing the windward end 12 a of the sub-louver 12into contact with the upper member 3 a defining the air outlet 3, thewindward end 12 a of the sub-louver 12 and the upper member 3 a definingthe air outlet 3 are in line contact with each other. In such a case,the points of contact between the two may vary with dimensional errorsof relevant components, assembly errors, and the like. Therefore, in thecase where the louver 10 is stopped by directly bringing the windwardend 12 a of the sub-louver 12 into contact with the upper member 3 adefining the air outlet 3, the position where the louver 10 (the mainlouver 11 and the sub-louver 12) stops may vary with different indoorunits 100.

In contrast, in the case where the louver 10 is stopped by bringing thewindward end 12 a of the sub-louver 12 into contact with the stopper 7,the windward end 12 a of the sub-louver 12 and the stopper 7 are inpoint contact with each other. Therefore, the variation in the positionwhere the louver 10 (the main louver 11 and the sub-louver 12) stopsoccurring with dimensional errors of relevant components, assemblyerrors, and the like is reduced. Hence, in the case where the louver 10is stopped by bringing the windward end 12 a of the sub-louver 12 intocontact with the stopper 7, the indoor unit 100 has much improved designin the state where the indoor unit 100 is not in operation.

REFERENCE SIGNS LIST

1: casing

2: air inlet

3: air outlet

3 a: upper member

3 b: lower member

4: fan

5: heat exchanger

6: straightening vane

7: stopper

10: louver

11: main louver

11 a: windward end

11 b: leeward end

11 c: virtual perpendicular line

12: sub-louver

12 a: windward end

12 b: leeward end

12 c: virtual perpendicular line

13: pin

14: rib

100: indoor unit

1. An indoor unit for an air-conditioning apparatus, comprising: acasing having an air inlet in an upper portion thereof and an air outletin a lower portion of a front face thereof; an air-sending deviceprovided in the casing and configured to suction air into the casing viathe air inlet and to blow the air out of the casing via the air outlet;a heat exchanger provided in the casing and configured to exchange heatbetween the air suctioned into the casing and a refrigerant; and alouver provided at the air outlet and configured to redirect the airblown out of the air outlet in a vertical direction, wherein the louverincludes a main louver and a sub-louver that each have a plate shape andare each configured to rotate around a rotational axis extending in alateral direction of the casing, and in a state where a virtual lineconnecting a leeward end and a windward end of the main louver is level,the sub-louver is provided below the main louver; a leeward end of thesub-louver is positioned forward by a first predetermined distance withrespect to a virtual perpendicular line passing through the windward endof the main louver; and a windward end of the sub-louver is positionedrearward by a second predetermined distance with respect to the virtualperpendicular line.
 2. The indoor unit for an air-conditioning apparatusof claim 1, wherein the air-sending device includes a plurality ofaxial-flow or mixed-flow fans that are provided in parallel on adownstream side of the air inlet, and the heat exchanger is provided onthe downstream side of the plurality of fans.
 3. The indoor unit for anair-conditioning apparatus of claim 1, wherein the sub-louver has asmaller width than the main louver in side sectional view.
 4. The indoorunit for an air-conditioning apparatus of claim 1, wherein, in a statewhere the sub-louver is provided such that a virtual line connecting theleeward end and the windward end thereof is level, a lower edge of theair outlet is positioned forward by a third predetermined distance withrespect to the windward end of the sub-louver.
 5. The indoor unit for anair-conditioning apparatus of claim 1, further comprising astraightening vane provided at an upper edge of the air outlet.
 6. Theindoor unit for an air-conditioning apparatus of claim 1, wherein themain louver and the sub-louver are configured to rotate around a commonrotational axis, and when the main louver and the sub-louver are rotatedabout the rotational axis, the windward end of the sub-louver comes intocontact with an upper edge of the air outlet and the main louver and thesub-louver cover the air outlet.
 7. The indoor unit for anair-conditioning apparatus of claim 6, further comprising a stopper thatis a projection provided on the upper edge of the air outlet, whereinthe windward end of the sub-louver is configured to come into contactwith the stopper.
 8. An air-conditioning apparatus comprising the indoorunit for an air-conditioning apparatus of claim 1.